Calculating Chemical Rates for Vines

Calculating chemical rates for vines

Viti-note Summary Once the dilute spray volume has been Concentrate spraying

- Dilute spraying determined, the amount of chemical to To determine water rate for concentrate - Concentrate spraying put in the spray tank needs to be spraying, the dilute water volume (point calculated. of run-off) is used in the calculation.

This determines the ‘concentration

factor’ which determines how much Dilute spraying chemical to put into the spray tank. For example, ‘point of run-off’ (dilute spraying) was determined to be 1,500 For example, a grower may wish to L/ha in a vineyard. The amount of apply 500 L/ha to reduce lost time agrochemical to add to the spray tank is filling up and returning to the specified on the label in mL per 100 L of chemical shed. water (e.g. 10 mL/100 L). In this example, Providing coverage is adequate at 500 the spray tank has a volume of 2,000 L. L/ha, a ‘concentration factor’ can be used

to apply equivalent agrochemical (as the dilute spray rate) with less water. The Sample calculation: calculation uses the dilute water volume Amount of chemical added to a 2,000 divided by the concentrate water volume:

litre tank = 10 mL/100 L X 2,000 L = 200 mL Sample calculation: Other topics in this Viti-Notes series include: Once mixed, the spray is applied to the 1500 L ÷ 500 L = 3 (i.e. 3 x vines at a rate of 1,500 L/ha (previously • Targeting sprays for concentration factor) vineyard pests and determined point of run-off). diseases The chemical application rate per hectare • Maintaining product can also be calculated: The dilute label rate from the chemical performance in spray Sample calculation: label is 10 mL/100 L then the concentrate mixes mixing rate becomes • Selecting and using spray Application rate = 10 mL/100 L x adjuvants 1,500 L/ha = 150 mL/ha Sample calculation: • Understanding chemical ‘modes of action’ 3 x 10 mL/100 L = 30 mL/100 L

• Managing chemical resistance in the vineyard • Equipment adjustment This then becomes the chemical rate per and evaluation to 100 L that is added to the tank. maximise spray coverage

• A single rate per hectare – why it shouldn’t be Sample calculation: used Amount of chemical added to a 2,000 • Determining chemical litre tank = 30 mL/100 L X 2,000 L = rates for dilute and concentrate spraying 600 mL

• Determining dilute water volumes for spraying • Calculating chemical rates for vines

Table 1. Details used in example below.

Vine canopy: Dense late season VSP

Dilute label rate: 10 mL/100 L (from the chemical label)

Spray tank volume: 2,000 L

Dilute spray volume to ‘thoroughly wet’ 1,500 L/ha the canopy being sprayed:

The chemical application rate per hectare can also be Acknowledgement calculated: The Australian Wine Research Institute would like to acknowledge the Cooperative Research Centre for Sample calculation: Viticulture (CRCV) and all involved in the Viti-notes Application rate = 30 mL/100 L X 50 0L/ha = series (1996 - 2006). 150 mL/ha

NOTE: CONCENTRATION FACTORS FOR DETERMINING A Further information CONCENTRATE MIXING RATE CAN ONLY BE CALCULATED Contact the AWRI helpdesk on 08 8313 6600 or ONCE THE DILUTE VOLUME HAS BEEN DETERMINED. [email protected]

www.awri.com.au

For region specific training in pest and disease control, contact the AWRI about the Research to Practice module: ‘Integrated Pest Management for changing viticultural environments’.

Other resources can also be found on the Wine Australia website: http://research.wineaustralia.com/

Agrochemical information Information about agrochemicals is published annually by the AWRI in a booklet titled Agrochemicals registered for use in Australian viticulture, commonly known as the ‘Dog book’. Access the latest version and the app from http://www.awri.com.au/industry_support/viticulture/ agrochemicals/agrochemical_booklet/.